Wood grinding machine



March 3, 1959 H. L. wENDsHLu-l WOOD GRINDING IVLACHINE Filed Deo. 11. 1956 Y WOOD GRINDING MACHINE Herbert L. Wendshuh, Appleton, Wis., assignor to The Appleton Machine Company, a corporation of Wisconsm Application December 11, 1956, Serial No. 627,661 Claims. (Cl. 241-228) This invention relates to a wood grinding machine, and is particularly concerned with means for feeding logs into the grinding zone of the machine.

The wood grinding machine comprises a feed ring rotatably mounted in a cylindrical housing and a grinding stone eccentrically mounted within the feed ring. The grinding stone cooperates with the feed ring to grind wood logs into paper stock. The paper stock, which comprises about 2% ground wood and 98% Water, ows through openings provided in the feed ring and into a discharge chute. i

The feed ring is described with particular reference to a wood grinding machine of the type disclosed in applicants copending application, Serial No. 609,581, filed September 13, 1956, but it will `be understood that it may be used with any suitable type of wood grinding machine. f

The feed ring of the present invention is cylindrical, and its outer edge portion is rigidly secured to a ring gear which is rotated slowly by a pinion. Two parallel seriesof shoes of plastic material, for example, a phenolformaldehyde condensation product such as is presently available under the trademarks Micarta and Bakelite, or other suitable material, are mounted on the outer surface of the feed ring. The shoes extend around the entire circumference of the feed ring and form substantially continuous bearing surfaces for the feed ring. Thek bearing surfaces are lubricated automatically as the feed ring is rotated. The shoes may be removed and replaced individually, as they become worn, without dismantling the machine.

The bottom case of the housing has a pairl of grooves into which the bearing shoes iit to prevent lateral displacement of the lower portion of the feed ring. The upper portion of the feed ring is stabilized by one or morepairs of guide rollers rotating about an axis at right angles to the axis of rotation of the feed ring.

The feed ring is rotated in the same direction as the grinding stone to force the logs toward the stone, thereby' obtaining the grinding actionrequired. The inner surface of the feed ring is provided with ribs projecting inwardly therefrom. These ribs are shaped to guide the logs into the grinding zone of the machine andV also cooperate with the peripheral surface of the grinding stone to provide efficient grinding of the wood in the grinding zone.

The bottom case of the housing is provided with va discharge outlet for the paper stock at each side 'of the machine. Perforated bale plates at opposite sides of the feed ring permit the'tiow of the paper stock into the discharge chute without permitting wood shims to pass through. The feed ring is also provided with openings leading directly to the discharge chute. A pair of deckle straps secured to the housing cover the gap between the housing and the edge of the feed ring to prevent the water from owing past the bearings and into the gearing.V If the deckle straps should allow passage of Water,

the bearings prevent such water from reaching the gears, s

'f is positioned 2,875,960 Arenamed Mal-3, 1959 AICC,

Z The shims are carried around to a doctor blade which near one edge of a return plate. The doctor blade removes the wood shims from the grinding stone and directs them into the space between the return plate and the feed ring. The inwardly extending ribs of the feed ring carry the shims across the machine where they are dropped at the feed end so that they may again move through the grinding operation. A s the Wood shims are being carried toward and across the top of the machine, theribs guide them towards the center of the feed ring to prevent their spilling over the edges of the feed ring.

The structure by means of which the above and other advantages are attained will be described in detail in the following specification, taken ,in conjunction with the accompanying drawing, showing a preferred illustrative embodiment of the invention, in which:

' t separated by Figure l is a vertical sectional view through the wood grinding machine, with parts broken away to illustrate the interior structure.

' Referring to the drawing, the reference numeral 2 indicates a base having a pair of Vparallel flat surfaces 3 upon which a cylindrical housing 4 is supported. Housing 4 is made in two parts, an upper case 5 and a bottom case 6 secured together in any suitable manner. Surfacesf3 extend beyond each end of the housing and are a channel 7 open at its top to receive a bulged wall portion 8 projecting outwardly from. the center portion of the housing around its entire periphery.

On opposite sides of the bulge 8, the housing has a pair of at surfaces 9 in engagement with the at surfaces 3. The housing 4 may be moved on base 2 by means of a screw (not shown). This movement of the housing is for the purpose of compensating for the wear on the grinding stone, hereinafter described, and is limited in extent.

The standards 10l at opposite sides of housing 4 support bearings 11 in alignment with each other along an axis eccentric to the center of housing 4. A shaft 12 journalled in bearingsY 11 extends through openings provided therefor in the side walls 13 of housing 4. Shaft 12 is rotated by a motor (not shown). A grinding stone 14 is mounted onvshaft 12 to rotate therewith. The

grinding stone is smaller in circumference than the interior of housing 4, and its axis is eccentric relative to the center of housing 4. The peripheral surface of the grinding stone cooperates with the inner surface of the feed ring to form a crescent shaped pocket constituting a grinding zone in which the wood logs are substantially ground to paper stock.

The width of grinding stone- 14 is less than the width ,y of the housing.- The grinding 'stone is centered, later-4 ally,

grinding stone 14 with just enough clearance to allow rotate freely.

the grinding stone to 16 are alike, and the description of Both baille plates one will apply to the otherV as well. The 'Dame plateV extends from the bottom of housing 4 to a point above the axis ofthe grinding stone. One edge of the bafe plate is curved to conform to the configuration of the inner surface of housing 4. The other edge of the baille plate is curved to conform generally to the peripheral., edge of the grinding stone which it overlaps slightly. A

plurality( of perforations 20 extend through the baille plate toy allow paper stockl to pass therethrough into v K the space ybetween the bathe plate and the adjacent side wall 13 of the housing. The space between the baffle plate 16 and side wall 13 forms part of a discharge chute 21jwhich extends from one end ofthe housing.

A ring gear 22 having teeth 23 onqits outer surface,

is rotatably mounted within the peripheral bulge 8 Vof housing 4.v The ring gear is driven by a motor (not shown) mounted on housing 4. The output shaft ofthe motor is operatively connected to a pinion which projects through an opening in the housing to mesh with ring gear 22. A circumferential'flange 24 extends inwardly from the center portion of the ring gear 22. v A feed ring 25, mounted within housing 4, is secured to flange 24 and rotates with the ring gear. The feed ring comprises two sections 26 and 27 for convenience of assembly. The inner edges of both sections are offset, as indicated at 28, to facilitate alignment of the two sections, and each section is provided with a peripheral flange 29 set backfrom its inner edge a distance equal to half the thickness of ange 24. Flanges 29 fit on opposite sides of flangeV 24, and all three anges are provided with registeringapertures to receive bolts 30 by means of which the feed ring sections are both secured to each other and to the ring gear. Both sections of the feed` ring are alike, so only one section will be described, the same reference numerals being applied to both sections.

Bearing shoes 31 are secured to the periphery of feed ring 25 in end to end relationship to furnish a continuous bearing surface. The shoes may be of plastic, for example, it may be a phenol-formaldehyde resinous condensation product such as that sold Iunder the trademark Ryertex or the trademark Insurok, or any other suitable material. Each shoe is in the form of a generally rectangular block curved slightly in its longitudinal direction to lit against the outer surface of the feed ring which is grooved, as indicated at 32, to provide a seat for .the shoes. If any shoe becomes worn it may be removed and replaced without disturbing the adjacent shoes.

The bottom case 6 of housing 4 is provided with a circumferential groove 33 on its inner surface which serves as a guide for bearing shoes 31, which t in said grooves, during their movement around fthe lower half of the housing. The grooves 33 cooperate with shoes 31 to prevent any lateral displacement or tipping of the lower half of the feed ring.

The upper half of the feed ring is stabilized by rollers 34 ywhich abut the lateral edges of the feed ring and are rotatable about an axis perpendicular to the axis of rotation of the feed ring. Each roller 34 has a shaft 35 which projects through an opening 36 in the housing. A support 37 holds each roller 34 against vertical displacement, and a yset screw 38, extending through a bracket 39 positioned adjacent the outer surface of housing 4, exerts lateral pressure against each support 37 to maintain roller 34 in juxtaposition with the side of feed ring 25 with a suitable lateral pressure.

The side walls`13 are each provided with 'an opening (not shown) for loading wood, preferably in the form of logs having a length slightly less than the width of the grinding stone 14, into the machine. The water necessary for the grinding operation is fed into the machine by a perforated pipe 40 extending transversely of the lhousingabove the grinding stone. The inner surface of feed n'ng 25 is provided with ribs 41 and 42 projecting inwardly therefrom for feeding the logs into the grinding zone.

The ri-bs 41 on each section 26 and 27 of the feed ring slope from the outer edge of the feed ring toward thel center, preferably at obtuse angles with respect to eachother as seen in the drawing, to -form a herringbone design with the inner ends of the ribs on each section offset from the inner edges of the ribs on the opposite section. As the'feed ring approaches the grinding fl zone the outer ends of the ribs 41 extend forwardly of the inner ends. The direction in which the ribs 41 are sloped causes the logs being moved by the feed ring towards the grinding zone to be moved laterally toward the center of the feed ring. This arrangement insures a more efficient grinding operation because it substantially prevents any of the logs from getting caught between the upper edge of either baffle plate 16 and the inner surface of the feed ring 25.

The ribs 42 extend circumferentially of the inner surface of the feed ring 25 and are positioned near the outer edges of the feed ring. Ribs 42 form ends for the annular grooves formed by each pair of adjacent ribs 41, and prevent any of the logs from sliding outwardly beyond the edges of the feed roll.

The ribs 41 and 42 have an additional function in that they cooperate with the peripheral surface of the grinding stone to insure ne grinding of the Wood. The grind-` ing stone rotates at a much greater rate of speed than the feed ring, and this diiference in the surface speed of the grinding stone and feed ring produces a tearing or shredding action on thewood.

The outer edges and the outer periphery of feed ring 25 are formed, as indicated at 43, to provide a space 44 between the feed ring and the housing 4. This space 44 forms part of the discharge chute 21. The feed ring is provided with three transversely spaced series of openings 45, 46 and 47. The openings 45, 46 and 47 extend through the feed ring angularly so that each opening leads to the space 44. The paper stock, in the form of a mixture of nely ground wood and water, that is discharged through these openings at the bottom of the feed ring ows into the space 44.

The paper stock is prevented from flowing into engagement with either the bearing shoes 31 or the ring gear 22 by means of a deckle strap 48 which extends around the bottom oase of housing 4 to cover the gap between the housing and the edge of feed ring 25 adjacent the inner edge of space 44. The ends of the deckle strap are rigidly secured to the upper half of housing 4 in any suitable manner. The securement of the deckle strap is adjustable so that the deckle strap may be kept taut in order to form an effective water seal. If any water does pass'the deckle strap it will be stopped by the bearing shoes 31 and will do no real damage since it cannot reach the gear. 22.

A doctor blade 49 `is pivotally mounted in housing 4, as indicated at 50, with its bevelled end 51 adjacent the periphery of grinding stone 14 just beyond the grinding Zone. The doctor blade extends across the entire width of the housing and removes any wood shims that might otherwise stick to the grinding stone and impair its efliciency. These shims are generally repelled by the stone. However, should they have a tendency to adhere to the stone, the doctor blade, acts as a stripper, and directs the shims outwardly against the ribbed inner surface of feed ring 25.

A return plate 52 curved to conform to the curvature of the `feed ring extends across the entire width of the housing and has its outer edges secured to side wall 13 of the housing 4. The return plate-52 cooperates with the -feed ring 25 to form a passageway for the return of the -shims from the discharge end of the grinding zone to the feed end of the machine. One edge of return plate 52 is positioned just above the top of doctor blade 49, so that shims directed outwardly by either the grinding stone or the doctor blade are caught in the passageway between the return plate 52 and the feed ring 25 and cannot drop until they are over the feed end of the machine.

The operation of the machine will now be described. The logs are loaded into the machine through an opening (not shown) in side wall 13, and water is fed through pipe 40. The grinding stone and feed ring are rotated in the same direction, but at different speeds. The internal ribs 41 and 42 on the feed ring engage the logs and move them laterally toward the center of the feed ring while moving toward the underside of the grinding stone. Since the logs cannot move backwards, they remain in the grinding zone between the inner surface of the feed ring and the peripheral surface of the grinding stone until they are substantially completely ground. The shims small enough to pass through the small clearance between the feed ring and the grinding stone are directed against the ribbed surface of the feed ring either by the grinding stone or by the stripping action of the doctor blade. The paper stock falls directly into the discharge area. The shims are moved by the ribs 41 and 42 across the upper half of the 'housing and then mixed with the logs introduced through the opening (not shown) in side wall 13.

The paper stock, which comprises approximately 2% ground wood and 98% water, flows through openings 45, 46 and 47 into space 44 which forms part of discharge chute 21. Additional paper stock flows through perforations 20 in bafe plate 16 into the discharge chute 21.

While I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description is intended to be illustrative, rather than restrictive, as many details may be modified or changed without departing from the spirit or scope of my invention. Accordingly, I do not desire to be restricted to the exact details of construction described.

I claim: l

1. A wood grinding machine having a housing, a feed ring rotatably mounted in the housing and means to drive said feed ring, said ring having a series of inwardly extending ribs on its inner surface, said ribs sloping forwardly from the center of said ring toward its outer edges.

2. A wood grinding machine comprising a housing, a feed ring rotatably mounted in said housing, means for rotating said feed ring, a grinding stone rotatably mounted in said housing and cooperating with said feed ring to form a grinding zone, and a series of inwardly extending ribs on the inner surface of said feed ring, said ribs being augularly disposed with their outer ends sloping forwardly toward said grinding stone on the portion of said feed ring adapted to move toward said grinding stone as said,v

feed ring is rotated,

3. A wood grinding machine comprising a housing, a feed ring rotatably mounted in said housing, a grinding stone cooperating with said feed ring to form a grinding zone, and a series of angularly disposed ribs on the inner surface of said feed ring and having the trailing portions of the ribs extending toward the feed ring center for guiding the wood laterally toward the center of said feed ring while moving it toward said grinding zone.

4. A wood grinding machine comprising a housing, a feed ring and a grinding stone rotatably mounted in said housing to form a grinding Zone, means for rotating said feed ring and grinding stone to grind logs in said grinding zone into paper stock comprising a mixture of ground wood and water, and a series of inwardly extending ribs on the inner surface of said feed ring, said ribs extending angularly inwardly from the feed ring edges and rearwardly of the feed ring with respect to the direction of movement of the feed ring to move said logs laterally toward the center of said feed ring as said feed ring is rotated.

5. A wood grinding machine comprising a housing, a feed ring rotatably mounted in said housing, means for rotating said feed ring, a grinding stone eccentrically mounted within said feed ring with one portion of the peripheral surface of said grinding stone engaging a portion of the inner surface of said feed ring to form a grinding zone for grinding logs into paper stock, and `a series of angularly disposed ribs extending inwardly from the inner surface of said feed ring, the ribs on opposite circumferential sections of said feed ring being disposed at obtuse angles with respect to each other to guide logs toward the lateral center of said feed ring and to simultaneously move said logs toward said grinding zone as said feed ring is rotated.

References Cited in the le of this patent UNITED STATES PATENTS 

